1999 MAZDA RX-7

Typical onset: 60,000-100,000 mi

Symptoms: Hard starting when hot, Low compression on one or both rotors, Excessive white/blue smoke on startup, Loss of power and poor fuel economy, Rough idle that worsens over time

Fix: Rotary engines wear apex seals that ride against rotor housings—once compression drops below 6.5-7 kg/cm² per rotor face, you need a full rebuild. Housings often need replacement if side seal grooves are worn or scarred. Quality rebuild with all new seals, bearings, and resurfaced housings takes 25-35 hours including removal/reinstall. Many owners upgrade turbos and seals during this process.

Estimated cost: $4,500-8,500

Typical onset: 70,000-120,000 mi

Symptoms: Loss of boost after 4,500 RPM, Check engine light with P0244 (wastegate solenoid), Overboosting or underboosting, Ratting noise from turbos under load, Oil smoke from exhaust at high RPM

Fix: The sequential system uses a complex vacuum-actuated setup where the secondary turbo engages around 4,500 RPM. Actuators seize, vacuum lines rot, and solenoids fail. Turbos themselves wear bearings or crack housings from heat cycles. Replacing both turbos with OEM units runs 18-22 hours; many opt for single-turbo conversions (15-20 hours) to eliminate the complexity.

Estimated cost: $2,800-6,000

Typical onset: 80,000-130,000 mi

Symptoms: Coolant disappearing with no visible leaks, White smoke from exhaust, Overheating under load, Milky appearance in coolant overflow tank, Steam from tailpipe on cold starts

Fix: Internal coolant seals between the rotor housings and irons fail, dumping coolant into the combustion chamber. No external leak, but you're constantly refilling. Requires complete engine disassembly—basically a full rebuild scenario. Some techs attempt seal replacement without full teardown (20-24 hours), but most recommend addressing apex seals simultaneously since you're already in there.

Estimated cost: $3,500-7,000

Typical onset: 60,000-90,000 mi

Symptoms: Hard starting, Lean condition codes, Rough idle and misfires, Hesitation on acceleration, Engine runs rich or soots plugs quickly

Fix: Primary and secondary injectors clog or fail—rotaries run four injectors per rotor. Original fuel pumps also weaken with age. Full injector service (clean or replace all four per rotor) plus pump replacement takes 6-8 hours. Use quality injectors; cheap ones fail fast under the rotary's heat and oil-rich environment.

Estimated cost: $1,200-2,200

Typical onset: 50,000-80,000 mi

Symptoms: Clunking on shifts or throttle engagement, Excessive driveline vibration, Difficulty getting into gear, Transmission appears to move excessively when viewed from underneath

Fix: Rubber mounts for the transmission and the rear subframe/differential tear and collapse from heat and age. Transmission mount replacement is straightforward (2-3 hours), but many do all subframe bushings at once while underneath (add 3-4 hours). Upgraded polyurethane mounts are common.

Estimated cost: $400-900

Symptoms: Check engine light for evap or air pump codes, Poor idle quality, Sequential turbo not engaging properly, Rats nest of cracked hard plastic lines under intake

Fix: The 13B-REW uses dozens of vacuum lines controlling turbos, idle control, emissions, and air injection. Lines become brittle, crack, and leak. The "rats nest" of emissions equipment under the upper intake manifold is infamous. Many owners delete the air pump system entirely (3-4 hours) and replace all vacuum lines with silicone (5-7 hours if doing it right).

Estimated cost: $600-1,400